Cholestyramine with Digitoxin Interaction Details

Brand Names Associated with Cholestyramine

  • Cholestyramine Resin
  • Locholest®
  • Locholest® Light
  • Prevalite®
  • Questran®
  • Questran® Light

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Last updated Feb 28, 2024

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Interaction Effect

Decreased digitoxin effectiveness

Interaction Summary

Cholestyramine can bind digitoxin in the gastrointestinal tract and alter its enterohepatic recycling, thereby altering the plasma level of digitoxin and its half-life[1][2]. Digitoxin toxicity has been successfully treated with cholestyramine [3][4].

Severity

Moderate

Onset

Delayed

Evidence

Probable

How To Manage Interaction

Since cholestyramine binds digitoxin in the gastrointestinal tract, administer digitoxin two hours before or four to six hours after cholestyramine. If this is not possible, separate administration times as much as possible. During concurrent therapy, monitor digitoxin serum levels closely and observe the patient for changes in response to digitoxin. Digitoxin dosage adjustments may be necessary when starting or stopping cholestyramine.

Mechanism Of Interaction

Decreased digitoxin absorption

Literature Reports

A) Ten patients were studied to examine the effects of cholestyramine and colestipol on digitalis therapy. Patients received 15 grams per day of colestipol, 12 grams per day of cholestyramine, or placebo 1.5 hours after the administration of either digoxin or digitoxin. Administration of colestipol or cholestyramine 1.5 hours after the cardiac glycoside, for long periods of time, was found to have no significant effect on serum cardiac glycoside levels compared to placebo [5].

B) Concomitant administration of digitoxin and cholestyramine can result in a reduction of digitoxin half-life from 11.5 days to 6.6 days, presumably by interruption of the enterohepatic circulation of digitoxin [6]. Digitoxin toxicity has been treated with cholestyramine with some success [7].

C) The effects of cholestyramine and spironolactone on the elimination rate of digitoxin were studied in six healthy volunteers. Subjects received digitoxin 0.1 mg to 0.15 mg for 30 days until steady-state plasma digitoxin levels were achieved. On day 31, the subjects were randomized to four treatment phases in which they received cholestyramine 4 grams eight times per day and spironolactone 300 mg per day, or a matched placebo of either drug. Not all of the subjects completed the four treatment phases. Coadministration of cholestyramine with digitoxin resulted in a decrease in digitoxin half-life from 141.6 hours to 84.4 hours [1].

D) A 72-year old woman was admitted to the hospital complaining of anorexia, vomiting, weakness, visual disturbances, and heartbeat irregularities. The patient was taking digitoxin 0.2 mg four times daily and diazepam 5 mg three times daily in addition to aspirin as needed. On admission, the patient had a blood pressure was 100/56 mm Hg and an ECG showed marked atrioventricular block, short QT interval, and periods of sinus arrest. Digitoxin level was measured to be 92 ng/mL (normal range 15 to 26 ng/mL). Fifteen hours later, the digitoxin level continued to be high, at 89 ng/mL. After the patient was started on cholestyramine 4 grams every six hours, the decrease in serum digitoxin levels was notably enhanced. By the time that cholestyramine therapy was discontinued, which was approximately 165 hours after the last dose of digitoxin, the digitoxin level had dropped to 31.5 ng/mL. The patient began to note improvement in symptoms and the degree of atrioventricular block gradually decreased [3].

References

    1 ) Carruthers SG & Dujovne CA: Cholestyramine and spironolactone and their combination in digitoxin elimination. Clin Pharmacol Ther 1980; 27:184-187.

    2 ) Baciewicz AM, Isaacson ML, & Lipscomb GL: Cholestyramine resin in the treatment of digitoxin toxicity. Drug Intell Clin Pharm 1983; 17:57-59.

    3 ) Pieroni RE & Fisher JG: Use of cholestyramine resin in digitoxin toxicity. JAMA 1981; 245:1939-1940.

    4 ) Bazzano G & Bazzano GS: Effect of digitalis-binding resins on cardiac glycoside plasma levels. JAMA 1972; 220:828-830.

    5 ) Bazzano G & Bazzano GS: Effect of digitalis-binding resins on cardiac glycoside plasma. Clin Res 1972; 20:24.

    6 ) Caldwell JH, Bush CA, & Greenberger NJ: Interruption of the enterohepatic circulation of digitoxin by cholestyramine. II. Effect on metabolic disposition of tritium-labeled digitoxin and cardiac systole intervals in man. J Clin Invest 1971; 50:2638-2644.

    7 ) Bazzano G & Bazzano GS: Digitalis intoxication. Treatment with a new steroid-binding resin. JAMA 1972a; 220:828-830.

Cholestyramine Overview

  • Cholestyramine is used with diet changes (restriction of cholesterol and fat intake) to reduce the amount of cholesterol and certain fatty substances in your blood. Accumulation of cholesterol and fats along the walls of your arteries (a process known as atherosclerosis) decreases blood flow and, therefore, the oxygen supply to your heart, brain, and other parts of your body. Lowering your blood level of cholesterol and fats may help to prevent heart disease, angina (chest pain), strokes, and heart attacks.

  • This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

See More information Regarding Cholestyramine Resin

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.


Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.


Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.


Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.